Advice requested for e-bike kit for Yuba Mundo

[spinningmagnets]

BionX makes a quality product. The sine - wave controller is built into the hub to eliminate 50% of the exposed wiring clutter. It is a little pricey (IMHO), but again...high quality.

It is a "flat land" system, and works great for that. It will get very hot on steep hills, and...if...the heat-protection is working? The power will be cut back (or cut off) on the steepest part of you hills. A direct drive hub with a sine - wave controller is so silent, its almost eerie. If some one gave me a 48V BionX for free...I'd make it into a custom stoke monkey on a longtail. That is the only way it's useful on steep hills.

 

[Ykick]

I never thought I would live to read “Bionx” and “pretty good price” in the same sentence!

Seriously, I believe a handy skilled person can approach most anything the Bionx can do using kit components.

But, if you like how something works via 1st hand test ride then you should stick to that. But I would also compare other setups as much as possible.

There’s a lotsa ways to go here so getting into the game can be confusing and easy to procrastinate. Majority of people who adopted this tech will ultimately build more than one so don’t worry too much about perfection as much as enjoying the ride. Whatever it may ultimately be!

 

[kiltedcelt]

So, since I last posted I've continued to do a lot more reading and I think now that the best buy money-wise that will fit most of my criteria is the Bafang BBS02 in 48v. I'm wondering though, if I really NEED to spend the extra to get a 750w version versus something like the 500w. Everything I mentioned before still applies as far as criteria. Probably 90 % of use of the bike as a daily commuter (currently 120+ miles per week), is almost unloaded - just myself (175 lbs), and two panniers (usually about 20 lbs max, if that even). So far the heaviest loads I've carried have been around 130 lbs or so, but I'd like to be able to manage carrying another person occasionally, so figure maybe up to around 200 lbs. once in a while. It's unlikely currently that I'd be carrying more than 200 pounds of cargo on this bike, but I'd like for the motor to be able to handle the full 600+ lbs. of cargo capacity (200 lbs rider + 440 lbs. cargo), if I ask it to. Top speed is unimportant, though ability to maintain at least 13-14 mph into a 20+ mph headwind, under pedal assist is paramount. I'm looking at the kits sold through em3ev, but I'm not sure if I should go with 36v or 48v and whether I should go 350w, 500w, or 750w, and finally what amp hour rating of battery to look at. I still want to be able to get my cardio workout while riding my bike so most of the time I'll be using it on either lowest assist level with full gear range (8 speed), or no assist at all. I think I'd reserve higher assist levels for getting up to speed and maintaining when riding on city streets (taking the lane), or rolling with cargo. I anticipate always having a place that I can charge the bike while at work if necessary so that shouldn't be an issue as far as range goes, and of course I can always plug it in for a full recharge overnight. So, that's it in a nutshell - what voltage do you think is acceptable in terms of cost and versatility, and what wattage of motor and amp-hour rating of battery. I'm assuming the best choices for weight and safety are still going to be LiFePo4 batteries, although I'll admit AGM batteries have crossed my mind, but GEEZ are they heavy, even in the mobility scooter sizes!

 

[amberwolf]

I'm wondering though, if I really NEED to spend the extra to get a 750w version versus something like the 500w.
How fast do you need to accelerate from a stop when loaded down? (to get out of the way of traffic behind you, for instance) The quicker you need to do that, the more power it will take.

Top speed is unimportant, though ability to maintain at least 13-14 mph into a 20+ mph headwind, under pedal assist is paramount.

If you're good and fit, then you could do that with 500w but you probably would get tired pretty quick that way. Takes my cargo bike about 500w to maintain 20MPH, so since you're talking about maintaining 33-34MPH (as far as air resistance goes) you're going to need more than that for the motor to do that alone. How much more, you'd have to either test or use the online calculators for this stuff (see the ES Wiki, linked in threads at the top of every forum).


Any lead batteries are going ot get at best half of their rating in Ah, less if you want them to last, don't work in cold very well, and just plain weigh too much. You throw away cargo capability by carrying the lead.

Any other battery you need to make sure you get enough Ah to allow it's C-rate to be capable of giving you the max sustained currents your system will pull. Even if you don't need the Ah for range, you need it for that.

 

[likes2bike]

I'm on the same build path as kiltedcelt.
The steps:
Got excited by Justin's Stoker at Maker Faire.
Ordered EM3 bat.
took my new EM3bat bag and went to bike store, to see if it fit the triangle.
Looked at Extracycle and Mundo side by side, decided on Mundo. Test rode V5: NICE!
Had decided to go Rohloff .
Uh oh, Mundo is 48 spoke, Rolloff 36. There goes the rim along with the derailleur.
Patterson crank? there goes the front derailleur.
Might as well buy a bare frame. Saleswoman calls Mundo. They don't sell bare frames anymore. Might have something to do with the fact that they have their own electric option.
Uh oh kilted says there is kickstand problem with IGH's chainline too.
Soo I'm on the same page with kilted, looking at a front hub motor (on another new thread)
Ideas anyone?

 

[amberwolf]

Maybe make your own bike?

It's not too hard....if you can't weld you can bold one together (see Dogman's threads; I have one I started that wya but never finished; jus tkept modifying my CrazyBike2 instead, which I'm still using several years later. (though the SB Cruiser trike is more useful for more types of cargo).

 

[kiltedcelt]

As likes2bike has found - doing an electrified Mundo seems to be a bit of a hassle. If you don't mind external gearing it seems like mid-drives like the Bafang BBS02 are the best, or something like a Stokemonkey. However, there are IGH cut-off switches that I've seen for sale which will cut motor power and thus not chew up the guts of an IGH when you shift gears (thus not under motor load at the time). As I understand it, this is not an issue with a front hub motor since you're not pushing motor power through the drivetrain. There's also a little bit more simplicity in the front hub motor design versus mid-drive, although mid-drive is apparently the undisputed king of torque and hill climbing ability. I'll likely still go with front hub on this bike simply for ease of not messing with my bottom bracket or needing any of the IGH cut-off rigamarole. Now, I'm just trying to figure out if I'd be better off with a geared hub front motor or a direct drive. A lot of what I've read still seems to point towards geared hub on the front.

As a side note, and mind you, I've not ridden a v5 Mundo, I believe you might still be able to find v4.3 Mundo frames available or buy a used v4.3 complete and only upgrade the parts you want - like the new rear wheel for the Rohloff. Incidentally, the new v5 is only something like 5 pounds lighter than the v4.3 so I don't really consider it a substantial upgrade over the hi-ten steel frame of the v4.3 which also has a cro-moly fork. On a bike that in stock build is over 50 lbs before you even start adding a motor and battery, 5 pounds in my opinion isn't really worth the extra cost. Call around and see if you can still get v4.3 frames by themselves. I built mine from a bare frame last year, just about three months before they came out with the v5. I was a little pissed to find out about the better frame just a scant few months later, but it sounds like I couldn't have bought just the frame anyway. Also, you might want to rethink the Rohloff if you go with e-assist. At least one thing I've read mentions that wide gear ranges on many of the IGHs goes unused in an e-assist build. Someone quoted a builder who electrified a bike with a Rohloff and ended up skipping two and three gears at a time due to the e-assist, essentially using about a third of the gear range of the hub. In m opinion that's a LOT of money to spend on a hub if you're not going to end up using the full range all the time.

 

[Chalo]

The reason to recommend Rohloff instead of another hub in an e-bike application isn't the number or spacing of the gears; it's the fact that the hub can transmit more power more reliably than other gearhubs. Same with the NuVinci.

If the Mundo doesn't fit the bill for whatever reason, there's always the Surly Big Dummy. It's not quite as stiff as the Mundo, but way stiffer than an Xtracycle Free Radical, compatible with all the Xtracycle accessories, and easily available as a bare frame. Surprisingly light, for what it is.

 

[kiltedcelt]

A Rohloff may be able to handle mid-drive torque better but at the price they sell at, it seems like a colossal waste of money. If it's one thing I've learned reading all of this stuff, that money would be better put into a higher capacity battery. As for NuVinci, after a recent experience with a wheel I build around an N360 hub, I would rather deal with Shimano and their limitations in cargo bike usage versus NuVinci. In short - NuVinci = no user serviceable parts, lame customer support, and absolutely no way to repair or refurbish a hub once it's out of warranty. No thanks. I'll take an Alfine any day over a NuVinci. They're specced on Larry vs. Harry Bullitts which is praise enough for me. I suppose if you completely turned off your e-assist you could then use the full range of the Rohloff, but for my money I'd rather have Shimano and put that extra money into batteries.

As for front hub motors - anyone care to offer any reasoning why direct drive might be better than geared or vice versa? I know the geared hub will freewheel so there's no drag like a hub motor. For a cargo bike, which would you pick and why? For the sake of keeping things simpler, let's cut any kind of mid-drive out of the equation and only suggest front hub options.

 

[Mundo]

I think allot depends on what battery you'd choose....

You should consider batteries with 20 AH or larger.

36 to 48 medium current - Geared Hub, they have good torque.

48 and above, medium to high current - Direct Hub

 

[Voltron]

Re. Direct drive vs geared, direct drive sheds heat better and has less to go wrong with it... but you def want to keep the rpms up or reduce power for steep slow climbs. I doubt you'll notice much handling difference with front drive as long as you're not starting on a slippery surface or doing steep off road climbing. I think you're in the right path that it's better to have a cheaper motor and a great battery than the other way around. But then again, there's a lot to be said for highly overpowered rear motor and charging any hill in your way at 30 to 35 too



Nothing like a Mundo for weight carrying and high speed stability to shorten up a commute

 

[Voltron]

And for carrying a passenger...thats when the extra power really comes in handy... so embarrassing making the girl (or whoever) get off and walk up the hill